I don't think people are (were) actually happy with it: Hence the immutable/FRP-ish UIs of React and similar frameworks. Of course they still have to cope with

I don't think people are (were) actually happy with it: Hence the immutable/FRP-ish UIs of React and similar frameworks. Of course they still have to cope with the realities of web browsers so there's still some ugliness in there, but the awfulness is mostly contained. (Though, you're absolutely right about CSS. It works fine for global state. The only problem is that "components", i.e. small bits of UI, aren't global.)